Silhoutte plates mounted on a pole, that can swing back and forth horizontally are put between two windows at a reaction range down here.
When you pop one, it swings into the other guys window, who has to pop it back.
There is also a walk thru with spring loaded popups triggered by different means, usually by a set of control wires/cables ran through conduit to the range operators table. He has a row of strings/wire in wooden dowels in little slots that he pulls at the right time, and that pulls the wire/string just enough to release the spring and pop up the bad guy, or bystander target. Works great.
The national gaurd training center down here uses motion sensors and electric eyes to activate little solenoid spring popups. You break the light beam, sends a current to the little thingy that releases the keeper on the popup.
Hope these help.